Back to EveryPatent.com
United States Patent | 5,247,995 |
Tjon-Joe-Pin ,   et al. | September 28, 1993 |
The invention shows a method of degrading damaging material within a subterranean formation of a well bore using an enzyme treatment. Filter cakes and very viscous fluids are such damaging materials. The enzyme treatment degrades polysaccharide-containing filter cakes and damaging fluids which reduces their viscosity. The degraded filter cake and damaging fluid can then be removed from the formation back to the well surface. The particular enzymes utilized are specific to a particular type of polysaccharide and are active at low to moderate temperatures. The enzymes attack only specific linkages in filter cakes and damaging fluids and are active in the pH range of about 2.0 to 10.0.
Inventors: | Tjon-Joe-Pin; Robert M. (Houston, TX); Brannon; Harold D. (Spring, TX); Rickards; Allan R. (Pinehurst, TX) |
Assignee: | BJ Services Company (Houston, TX) |
Appl. No.: | 910050 |
Filed: | July 8, 1992 |
Current U.S. Class: | 166/312; 166/300; 507/201; 507/921; 507/928 |
Intern'l Class: | E21B 037/08; E21B 043/25 |
Field of Search: | 166/300,305.1,312 252/8.551,8.552 |
2602778 | Jul., 1952 | Snyder | 166/312. |
2681704 | Jun., 1954 | Menaul | 166/283. |
3044550 | Jul., 1962 | Ellers. | |
3684710 | Aug., 1972 | Cayle et al. | 252/8. |
4160483 | Jul., 1979 | Thomas et al. | 166/307. |
4342866 | Aug., 1982 | Kang et al. | 536/119. |
4343363 | Aug., 1982 | Norton et al. | 166/281. |
4410625 | Oct., 1983 | Cadmus | 435/42. |
4479543 | Oct., 1984 | Kalfayan et al. | 166/300. |
4609475 | Sep., 1986 | Hanlon et al. | 252/8. |
4690891 | Sep., 1987 | Hou et al. | 435/42. |
4713449 | Dec., 1987 | Vanderslice et al. | 252/8. |
4809783 | Mar., 1989 | Hollenbeck et al. | 166/307. |
4886746 | Dec., 1989 | Cadmus et al. | 435/42. |
4996153 | Feb., 1991 | Cadmus et al. | 435/209. |
5032297 | Jul., 1991 | Williamson et al. | 166/305. |
5067566 | Nov., 1991 | Dawson | 166/308. |
5165477 | Nov., 1992 | Shell et al. | 166/300. |
Foreign Patent Documents | |||
0030393 | Jun., 1981 | EP. |
M. E. Slodki and M. C. Cadmus, "Production and Stability of Xanthan Gums; Xanthanases and Their Applicability", Microbes and Oil Recovery, vol. 1, 1985, pp. 190-199. M. C. Cadmus and M. E. Slodki, "Enzyme Breakage of Xanthan Gum Solution Viscosity in the Presence of Salts", Developments in Industrial Microbiology, 1985, Chap. 18. M. C. Cadmus and M. E. Slodki, "Bacterial Degradation of Xanthan Gum", Industrial Polysaccharides: Genetic Engineering, Structure/Property Relations and, Applications, 1987, pp. 101-107. |
TABLE I ______________________________________ Damage Permeability Test TEMP EFFECT ON PERME- .degree.F. TIME FILTER CAKE ABILITY ______________________________________ 150 0 MINUTES INTACT 0 150 30 MINUTES UNDISSOLVED RESI- 0 DUE 150 45 MINUTES INCOMPLETE DIS- 50% SOLUTION 150 1 HOUR COMPLETE DISSOLU- 97 + % TION ______________________________________